Hi. I have an peculiar problem with a new floor installation. We had 4500 sq ft of 3/4" white oak, 2 1/4" wide, installed in a new build at the beach. They were nailed down over Advantec subfloor after a week of acclimation with the HVAC on, winter time. A few months after the install, the floors were stained with Minwax classic gray and finished with 3 coats of Bona Mega. When the build was finished, the floors were horribly scuffed so the flooring contractor recently did a buff and recoat with Bona Traffic HD. We kept the house locked up for two weeks to ensure a good cure. My first day back in the house I noticed a crackling sound with every step, throughout the house (3 floors). At first I thought it was my shoes but it continued even in stocking feet. These floors were absolutely silent prior to the recoat. The sound is subtle and sounds like Rice Krispies. No popping or movement that I noticed. Does anyone know what could be happening here? All thoughts, insights and advice are really appreciated. I'm meeting with the builder next week.